AP Psychology Unit 1 Vocab

Heredity

The genetic transmission of traits from parents to offspring through genes.

Nature & Nurture

The debate over the relative contributions of genetics (nature) and environmental influences (nurture) to behavior and development.

Eugenics

A historically discredited movement aimed at improving the genetic quality of a population through selective breeding; widely criticized as unethical.

Central Nervous System (CNS)

The brain and spinal cord; responsible for processing information and directing behavior.

Peripheral Nervous System (PNS)

The network of nerves outside the CNS that connects the brain and spinal cord to the rest of the body.

Autonomic Nervous System (ANS)

A division of the PNS that controls involuntary functions such as heart rate, digestion, and gland activity.

Somatic Nervous System

A division of the PNS that controls voluntary movements of skeletal muscles.

Parasympathetic Nervous System

A division of the ANS that calms the body and conserves energy (rest-and-digest functions).

Sympathetic Nervous System

A division of the ANS that arouses the body and mobilizes energy (fight-or-flight response).

Neural Cells

General term for cells in the nervous system, including neurons and glial cells, that process and support communication.

Glial Cells (Glia)

Supportive cells in the nervous system that nourish, protect, and insulate neurons and assist in neural functioning.

Neurons

Nerve cells that are the basic building blocks of the nervous system, responsible for receiving and transmitting information.

Reflex Arc

A simple, automatic neural pathway that controls reflexes, allowing rapid responses without conscious brain involvement.

Sensory Neurons (Afferent Neurons)

Neurons that carry incoming information from sensory receptors to the brain and spinal cord.

Motor Neurons (Efferent Neurons)

Neurons that carry outgoing signals from the brain and spinal cord to muscles and glands.

Interneurons

Neurons within the brain and spinal cord that process information and connect sensory neurons to motor neurons, enabling internal communication in the central nervous system.

All-or-nothing principle

The rule that a neuron fires an action potential at full strength once the threshold is reached; if the threshold is not met, the neuron does not fire at all.

Depolarization

A phase of the action potential when the inside of the neuron becomes less negative (more positive) due to the influx of sodium ions, increasing the likelihood of firing.

Refractory period

A brief time after an action potential during which a neuron cannot fire again (absolute) or requires a stronger stimulus to fire (relative), allowing the neuron to reset.

Resting potential

The stable, negative charge of a neuron when it is not firing (about -70 mV), maintained by ion distribution across the membrane.

Reuptake

The process by which neurotransmitters released into the synapse are reabsorbed by the sending neuron, stopping their signaling effect.

Threshold

The minimum level of stimulation required to trigger an action potential in a neuron.

Multiple Sclerosis

A neurological disorder in which the immune system attacks the myelin sheath, disrupting communication between the brain and body.

Myasthenia Gravis

An autoimmune disorder that affects communication at the neuromuscular junction, causing muscle weakness due to blocked or destroyed receptors.

Neurotransmitters

Chemical messengers that transmit signals across the synapse from one neuron to another.

Excitatory Neurotransmitters

Neurotransmitters that increase the likelihood that the receiving neuron will fire an action potential.

Inhibitory Neurotransmitters

Neurotransmitters that decrease the likelihood that the receiving neuron will fire an action potential.

Action Potential

A rapid electrical impulse that travels down the axon of a neuron, allowing it to communicate with other cells.

Dopamine

A neurotransmitter involved in movement, learning, attention, and emotion; often associated with reward and motivation pathways.

Serotonin

A neurotransmitter that regulates mood, hunger, sleep, and arousal; low levels are linked to depression.